Used primarily as an antihistamine in pharmaceutical formulations, this compound helps alleviate allergic reactions by blocking histamine H1 receptors. It is effective in treating symptoms such as sneezing, itching, and runny nose associated with seasonal allergies and upper respiratory infections. Due to its lipophilic nature, it crosses the blood-brain barrier, which contributes to its sedative effects—making it useful in nighttime allergy medications and some over-the-counter sleep aids. It may also exhibit anticholinergic properties, aiding in reducing nasal secretions and providing relief in cold remedies.